The invention relates generally to computerized circuit design systems and, more particularly, to a system and method for disabling components in schematic diagrams of electronic circuits. It will be appreciated that the invention finds particular application to software programs for creating and testing circuit schematics but also applies to other types of design tools such as Computer Aided Design (CAD) applications and hardware description languages.
Schematic diagrams are considered by many circuit designers to be the most intuitive method of circuit design entry. Schematic diagram software programs allow a circuit design to be entered into computer memory in the form of a schematic diagram comprising circuit component symbols connected by signal paths (interconnection lines/nets). A circuit designer can xe2x80x9creadxe2x80x9d a schematic diagram displayed on a video screen and understand the interrelationships of the circuit components without a specialized knowledge of the schematic diagram software program.
A typical schematic diagram software program includes several software tools including a component generator for defining circuit components, a schematic editor for editing a schematic, a display generator for displaying the schematic and a netlist generator for creating a netlist file. A netlist is a computer memory file that describes the corresponding schematic diagram in a text based hardware description language. The netlist file includes a list of components (logic gates, flip flops, etc.) and interconnections between the components which represent a circuit design of the schematic. The component generator allows a user to define and store schematic components in a schematic component library.
A schematic component is comprised of two parts, namely, a schematic symbol which is displayed on a video monitor, and an underlying circuit design which defines the function of the schematic component. Schematic components are recognized by the design program as representing the functions of their underlying circuit designs. After completion of the schematic diagram, the netlist generator reads the schematic diagram and converts the circuit design into a netlist file. The netlist differs from a schematic diagram in form. The schematic diagram is a graphical illustration easily recognized by a user, while the netlist is a list of components and the lines which interconnect them, and is easily manipulated by a computer.
In order to test that a circuit is properly constructed to perform a desired function, the netlist file of the schematic is executed by a circuit simulator or synthesis application, which may include additional file format conversions to be readable by the simulator. Simulation of a circuit, however, can be time consuming and designers sometimes need to remove parts of the circuit either because they are not completed or because the designer wishes to focus on the other portions of the circuit. To accomplish this, the design would physically cut-out a sub-circuit from the schematic and paste it to another drawing sheet. In this manner, the netlister would not see the cut-out sub-circuit and, thus, it would not be executed by the simulator. Then to place the sub-circuit back into the schematic, it would have to be cut and pasted back in with the appropriate connections of wiring being made. This process is time consuming for the designer.
According to one embodiment of the present invention, a schematic editor for defining a schematic that is a graphical representation of an electrical circuit is provided. The schematic editor includes a schematic designer that allows a user to select one or more electrical components represented in graphical form and allows the user to connect the electrical components to define an electrical circuit describing a desired function. A disabling routine is provided that allows the selection of a portion of the electrical circuit and disables that portion.
According to a more limiting aspect of the present invention, the disabling routine disables an associated sub-function of the selected portion without removing the selected portion from the schematic diagram.
According to another embodiment of the present invention, a method of designing a schematic diagram of an electrical circuit is provided. One or more electrical components are provided for selection where the electrical components are represented in a graphical form. Connectivity of input and output signal lines to the electrical components can be made to define a schematic diagram of an electrical circuit that performs a first function when executed by a simulator. A user may select a sub-circuit within the electrical circuit such that the electrical circuit includes the selected sub-circuit and a non-selected sub-circuit each having an associated function. The associated function of either the selected sub-circuit or the non-selected sub-circuit is disabled from the electrical circuit causing the electrical circuit to perform a second function when executed by a simulator.
According to a more limiting aspect of the present invention, a dummy component and/or value is assigned in place of the disabled associated function.
One advantage of the present invention is that a user can easily and automatically disable a portion of a schematic diagram.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.